9. Microorganisms in abscesses often are not killed by antimicrobial
agents because A. the microorganisms stop dividing. B. of
the chemical nature of the pus. C. of the lack of blood
vessels. D. of the high level of oxygenation. E. the
microorganisms stop dividing, of the chemical nature of the pus AND of
the lack of blood vessels.

E. the microorganisms stop dividing, of the chemical nature of the
pus AND of the lack of blood vessels.

10

10. An important feature of many wounds that may lead to more serious
problems is that they are A. well aerated. B. well
fed. C. sterile. D. relatively anaerobic.

41. Which is true about protein A? A. It binds to the Fc
region of antibody. B. It hides bacteria from phagocytes.
C. It enhances binding of phagocytes. D. It digests
antibodies. E. It binds to the Fc region of antibody AND it
hides bacteria from phagocytes.

E. It binds to the Fc region of antibody AND it hides bacteria from phagocytes.

41

42. Which is true of leukocidins? A. They are
superantigens. B. They kill neutrophils. C. They make
holes in host cell membranes. D. They bind to Fc regions of antibodies.

56. What is NOT a reason why an abscessed wound might not respond to
antibiotic treatment? A. The bacteria within the abscess have
ceased replicating, and many antibiotics require actively replicating
cells in order to be effective. B. The blood vessels that would
bring the drug to the area have been destroyed or clogged with clots,
preventing the drug from getting to the microbes in the abscess.
C. The bacteria in an abscess have all acquired multi-drug antibiotic
resistance, so any drugs that are used will have no effect. D.
The chemical composition of the pus in the abscess often inactivates
antibiotic drugs, making them ineffective.

C. The bacteria in an abscess have all acquired multi-drug antibiotic
resistance, so any drugs that are used will have no effect.

44

57. Why is it not surprising that Staphylococci are the
leading cause of wound infections? A. This genus is readily
present as a part of the normal microbiota on most people's skin, so
it could easily enter wounds.

B. Members of this genus are all particularly virulent and highly
capable of causing numerous infections. C.
Staphylococci cannot be eradicated from the skin due to
multidrug resistance in most members of the genus. Drugs simply don't
kill them. D. Staphylococci are capable of a higher
degree of spontaneous mutation than most microbes. This makes them
able to acquire antibiotic resistance very readily, making them hard
to eliminate by pre-surgical antibacterial scrubs. As such, they
commonly infect surgical wound sites.

A. This genus is readily present as a part of the normal microbiota
on most people's skin, so it could easily enter wounds.

45

58. Would babies need to be immunized against lockjaw (tetanus) if
their mother had been immunized against the disease? Why or why not?
A. No-because the mother's IgG antibodies would be passed along
through the placenta before birth, protecting the baby from the
infection. B. Yes-because even though maternal IgG antibodies
might be passed along through the placenta, they will not last
forever. The baby will need to create its own antibody response to be
protected against future tetanus. C. No-because maternal IgG
antibodies would be passed along in the breast milk, protecting the
baby from infection.

B. Yes-because even though maternal IgG antibodies might be passed
along through the placenta, they will not last forever. The baby will
need to create its own antibody response to be protected against
future tetanus.

46

59. Why might Candida albicans become pathogenic in an
individual receiving antibacterial medications? A. This fungal
organism can actually utilize the destroyed bacterial cells as a
nutrient source and begin to multiply out of control. This can cause a
pathogenic state. B. This is an opportunistic pathogen not
normally found in normal microbiota. As such, when the bacterial
normal microbiota is wiped out by broad-spectrum antibacterial drugs,
this opportunist can adhere to and colonize the area left behind.

C. This is a usual member of the normal microbiota. However, when
the bacterial members of the normal microbiota are wiped out by a
broad-spectrum antibacterial drug, this fungal cell type has little to
no competition for resources in the affected area. As such, it quickly
overgrows and can cause a pathogenic state.

C. This is a usual member of the normal microbiota. However, when the
bacterial members of the normal microbiota are wiped out by a
broad-spectrum antibacterial drug, this fungal cell type has little to
no competition for resources in the affected area. As such, it quickly
overgrows and can cause a pathogenic state.

47

60. Rowley Pharmaceutical company produces a drug that promotes new
blood vessel growth. Is there any application for this drug in wound
treatment? A. It could be very beneficial-one of the biggest
problems with wound infections is their largely anaerobic nature. The
blood supply to the area is usually compromised, helping to create the
anaerobic environment. Certain pathogenic microbes then thrive in this
environment, creating very serious wound infections. B. It
could be disastrous! Part of the reason abscesses lack blood flow is
to keep toxins and bacteria from spreading to other areas of the body.
Increasing blood flow to the area will provide a highway for these
bacteria to seed other organ systems! C. It could be
dangerous-wounds need to cut off blood supply to prevent the patient
from bleeding to death. Increasing blood vessel development in the
wound site might cause the patient to bleed out. D. There would
be no beneficial effect-the immune response is already in place in the
wound site, so increasing blood cell delivery to the area wouldn't
increase or decrease the rate of wound healing.

A. It could be very beneficial-one of the biggest problems with wound
infections is their largely anaerobic nature. The blood supply to the
area is usually compromised, helping to create the anaerobic
environment. Certain pathogenic microbes then thrive in this
environment, creating very serious wound infections.

48

1. Who determined that the cholera outbreak in 1850s London was due
to contaminated water and approached the problem by removing the pump
handle at the contaminated site? A. Pasteur B. Snow
C. Koch D. Smith

6. Part of the ability of S. mutans to produce dental caries
depends on its ability to A. invade plaque and dissolve the
gums. B. convert sucrose to lactic acid. C. convert
proteins to sugars. D. attach to the gums.

25. Shigella A. are themselves nonmotile. B.
may be pushed from cell to cell by actin tails. C. utilize pili
to move. D. utilize flagella to move. E. are themselves
nonmotile AND may be pushed from cell to cell by actin tails.

E. are themselves nonmotile AND may be pushed from cell to cell by
actin tails.

73

26. Which of the following groups contain diarrhea-causing E.
coli? A. enterotoxigenic B. enteroinvasive C.
enteropathogenic D. enterohemorrhagic E. All of the
choices are correct.

E. All of the choices are correct.

74

27. Which of the following groups give rise to a disease similar to
that caused by Shigella sp.? A. enterotoxigenic
B. enteroinvasive C. enteropathogenic D.
enterohemorrhagic E. All of the choices are correct.

B. enteroinvasive

75

28. Which group produces a toxin somewhat similar to that produced by
Shigella dysenteriae? A. enterotoxigenic B.
enteroinvasive C. enteropathogenic D.
enterohemorrhagic E. All of the choices are correct.

47. Most North American outbreaks of Cyclosporacayetanensis have been associated with A.
cattle. B. iguanas. C. imported leafy vegetables and berries.

D. chickens.

C. imported leafy vegetables and berries.

95

48. The oocytes of Cyclosporacayetanensis
A. are mature when eliminated in the stool. B. do not contain
sporozoites when passed in the feces. C. are smaller than the
oocytes of Cryptosporidiumparvum. D. give
rise to three sporozoites. E. All of the choices are correct.

B. do not contain sporozoites when passed in the feces.

96

49. Entamoebahistolytica A. causes
amebiasis. B. may form cysts. C. cysts survive passage
through the stomach. D. may produce a cytotoxic enzyme. E.
All of the choices are correct.

E. All of the choices are correct.

97

50. Amebiasis A. is caused by .

B. often causes a bloody diarrhea. C. is an infection of the
stomach. D. is restricted to temperate climates. E. is
caused by AND often causes a bloody diarrhea.

B. often causes a bloody diarrhea.

98

61. Why is it that the tongue and cheek epithelium doesn't provide a
sufficient anaerobic environment for plaque anaerobes to grow, but the
surface of teeth might? A. The epithelium is supplied with
oxygen by capillary beds. This makes it a relatively aerobic
environment and hostile to anaerobes. B. The tooth enamel is
supplied with oxygen by capillary beds. This makes it a relatively
anaerobic environment and hostile to aerobes. C. The surface of
the tongue and cheek are constantly scraped by the action of consuming
food. Layers of bacterial growth that might help to supply an
anaerobic environment are scraped away, exposing lower levels to
oxygen-rich air. D. The surface of teeth (especially the
molars) have many pits and crevices that can serve as 'pockets' for
layers of bacteria to grow in. Once the layers get deep enough, the
bottom portions are anaerobic. This isn't possible on the very smooth
surface of the tongue and cheek epithelium.

A. The epithelium is supplied with oxygen by capillary beds. This
makes it a relatively aerobic environment and hostile to anaerobes.

99

62. Explain how Vibrio cholerae causes cholera without
apparent damage to the intestinal epithelium. A. This microbe
causes destruction of the cellular structures underneath the
intestinal epithelium-this is what induces the watery rice-stool
characteristic of the illness. This leaves the overlying intestinal
epithelium intact. B. This microbe directly invades the
intestinal epithelial cells, but does not kill them. Instead, while
multiplying inside them, it causes them to secrete large amounts of
chloride ions. This induces water to follow by osmosis, resulting in
the watery rice-stool characteristic of the illness. C. This
microbe attaches to the surface of intestinal epithelial cells,
secreting an exotoxin that causes the epithelium to secrete large
amounts of chloride ions. This induces large amounts of water to
follow by osmosis, resulting in the watery rice-stool characteristic
of the illness. D. The inflammatory reaction to the presence of
this microbe causes the watery rice-stool characteristic of the
illness. Therefore, it's technically the immune response that
initiates the disease, although this response is induced by the
presence of the microbe on the intestinal epithelium.

C. This microbe attaches to the surface of intestinal epithelial
cells, secreting an exotoxin that causes the epithelium to secrete
large amounts of chloride ions. This induces large amounts of water to
follow by osmosis, resulting in the watery rice-stool characteristic
of the illness.

100

63. Why might it be more difficult to prepare a vaccine against
noroviruses than against rotaviruses? A. We haven't been able
to culture noroviruses in a lab setting yet. Without a starting
culture, we can't create a vaccine. B. Noroviruses are RNA
viruses, where rotaviruses are DNA viruses. RNA viruses mutate far
more easily than DNA viruses, so we COULD make a vaccine, but it would
be rendered useless fairly quickly as the virus mutates. C. We
lack a proper culturing method for large-scale production of target
cells for norovirus, whereas we have such a system for the target
cells of rotaviruses. Without a system to get large numbers of target
cells, we can't produce a vaccine. D. Norovirus is much more
infectious than rotavirus. As such, it's much harder to work with
safety. This makes production of a vaccine too dangerous and unpredictable.

A. We haven't been able to culture noroviruses in a lab setting yet.
Without a starting culture, we can't create a vaccine.

101

64. Would you expect an individual with giardiasis who has diarrhea
to be more likely to transmit the disease than an individual with
giardiasis who does NOT have diarrhea? Why or why not? A. No.
This illness is spread by respiratory droplets, so diarrhea as a
symptom shouldn't matter for transmission of the disease. B.
No. This illness is spread by sexual contact, so diarrhea as a symptom
shouldn't matter for transmission of the disease. C. Yes. This
illness is spread by the fecal-oral route, so presence of diarrhea as
a symptom should dramatically increase the possibility of transmission
of infection. D. Yes. This illness is spread by insects that
feed on contaminated fecal matter, becoming infected themselves. The
disease is spread to new individuals when these infected insects bite
a susceptible person, transmitting the cysts of the protozoan. As
such, diarrhea as a symptom would increase the risk of transmission
through biting insects to new individuals. E. No. This illness
is spread when people ingest cysts, and a person with severe diarrhea
excretes primarily trophozoites; an asymptomatic person is more likely
to excrete cysts and is therefore more infectious.

E. No. This illness is spread when people ingest cysts, and a person
with severe diarrhea excretes primarily trophozoites; an asymptomatic
person is more likely to excrete cysts and is therefore more infectious.

102

1. The scientist responsible for the development of the first
anti-plague vaccine in 1866 was A. Alexandre Yersin. B.
Robert Koch. C. Louis Pasteur. D. Josef Marburg.

25. The development of lymph node enlargement in the region of a skin
ulcer after a tick or insect bite or handling of a wild animal
suggests A. brucellosis. B. endocarditis. C.
septicemia. D. tularemia.

45. Which of the following is caused by a protozoan infection?
A. malaria B. yellow fever C. tularemia D.
infectious mononucleosis

A. malaria

146

46. Which of the following is transmitted by mosquitoes? A.
plague B. yellow fever C. malaria D. tularemia
E. yellow fever AND malaria

E. yellow fever AND malaria

147

47. Which species of Plasmodium causes the most serious form
of malaria? A. ovale B. malariae C. vivax D. falciparum

D. falciparum

148

48. In which of the following diseases does the spleen enlarge?
A. infectious mononucleosis B. malaria C.
leishmaniasis D. brucellosis E. All of the choices are correct.

E. All of the choices are correct.

149

59. What is the difference between 'bacteremia' and 'septicemia?'
A. Bacteremia is an infection with bacteria. Septicemia is an
infection with Septic protozoans. B. Bacteremia is the
presence of living, multiplying bacteria in the bloodstream.
Septicemia is the presence of endotoxins, but not necessarily of
living microbial agents. C. Septicemia is the presence of
living, multiplying bacteria in the bloodstream. Bacteremia is the
presence of endotoxins, but not necessarily of living microbial
agents. D. There is no difference-both terms denote the
presence of living bacterial cells in the bloodstream.

B. Bacteremia is the presence of living, multiplying bacteria in the
bloodstream. Septicemia is the presence of endotoxins, but not
necessarily of living microbial agents.

150

60. How would crowded conditions in cities favor spread of plague?
A. Plague is transmitted by rats-more people means more waste,
and more waste means more rats. This would favor the spread of plague.
B. Plague is transmitted by mosquitoes-more people close
together gives an infected mosquito more chances to bite humans and
transmit the causative agent, spreading plague. C. Plague is
transmitted by infected fleas-these fleas may be found on rodents
(such as rats). More people in an area means a greater chance of
interactions with animals carrying infected fleas, increasing the
spread of plague. D. Plague is transmitted by direct contact
(e.g. skin to skin). More people in an area provides more chances for
infected individuals to directly contact and infect other individuals,
spreading plague.

C. Plague is transmitted by infected fleas-these fleas may be found
on rodents (such as rats). More people in an area means a greater
chance of interactions with animals carrying infected fleas,
increasing the spread of plague.

151

61. Why does it take more than a week before a mosquito just infected
with yellow fever virus can transmit the disease? A. The virus
must replicate in the gut of the mosquito before it can reach high
enough numbers for transmission to a new human. B. Mosquitoes
only feed once a week, which limits their ability to transmit the
disease rapidly. C. Yellow fever is caused by a protozoan. It
must develop from the sporozoite form into the mature form to become
infectious, and this takes time. D. The virus multiplies in the
gut of the mosquito, but then needs to migrate to the proboscis
(biting nose) of the animal in order to infect a new human being after
a new bite. This migration takes time.

A. The virus must replicate in the gut of the mosquito before it can
reach high enough numbers for transmission to a new human.